Utjecaj obrade površine nano-silike na svojstva PLA kompozita

master's thesis

• Title (english): Influence of nano-silica surface pretreatment on the PLA composite properties
• Author: Ana Peranić
• Mentor: Mirela Leskovac (mentor)
• Committee member: Mirela Leskovac (predsjednik povjerenstva)
• Committee member: Vesna Ocelić Bulatović (član povjerenstva)
• Committee member: Lidija Furač (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2017-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

U novije vrijeme sve je veći interes za pronalazak materijala koji bi konkurirali na tržištu svojim dobrim svojstvima, biodegradaciji i proizvodnji iz obnovljivih izvora energije. Biopolimeri se danas sve češće koriste kako bi se smanjio negativan utjecaj na okoliš koji imaju polimeri. Jedan od poznatih biorazgradivih polimera je polilaktid. Dodatakom sintetskih ili prirodnih anorganskih materijala polimernoj matrici moguće je poboljšati svojstva polimernih materijala i sniziti cijenu koštanja materijala. U ovom radu istražen je utjecaj dodatka punila (A200, R711, R805 i R816) različitih udjela na svojstva polilaktida. Uzorci su zamiješani u Brabender gnjetilici postupkom u talini. Interakcije na međupovršini punilo/matrica ispitane su metodom mjerenja kontaktnog kuta. Mehanička svojstva i mehanizam loma ispitani su rasteznim ispitivanjem na mehaničkoj kidalici. Toplinska svojstva ispitivana su metodom diferencijalne pretražne kalorimetrije, a toplinska stabilnost termogravimetrijskom analizom. Rezultati mjerenja kontaktnog kuta s vodom ukazuju na slabu hidrofilnost površine polilaktida. Punila A200 i R816 pokazuju hidrofilnu, a R711 i R816 hidrofobnu prirodu površine punila. DSC analiza je pokazala da dodatak neobrađenog A200 i silanima obrađenog silika punila u PLA matricu nema utjecaja na staklište PLA. Punilo doprinosi porastu stupnja kristalnosti i pokazuje nukleacijski učinak na kristalizaciju PLA. U PLA kompozitima metakril silanom R711 i oktilsilanom R805 obrađeno punilo usporava kristalizaciju PLA matrice. Dodatkom različitih udjela punila toplinska stabilnost PLA matrice se povećava. Rezultati ispitivanja mehaničkih svojstava pokazali su da dodatkom punila u čistu PLA matricu nema značajnih promjena u produljenju. Sve krivulje pokazuju krti lom uz maksimalno istezanje do 4%. Najbolja mehanička svojstva pokazuju PLA/R711 kompoziti.

Abstract (english)

More recently, there is an increasing interest in finding materials that would compete in the market with its good properties, biodegradation and renewable energy production. Biopolymers are increasingly used today to reduce the adverse environmental impact of polymers. One of the wide known biodegradable polymers is polylactide. By adding synthetic or natural inorganic materials to the polymer matrix properties of the polymeric materials could be improved and the price of the material could be lowered. In this study the effect of filler addition (A200, R711, R805 and R816) in different quantities in polylactide was investigated. Samples were prepared by melt mixing in a Brabender plasticoder. Interactions on the filler/matrix interphase were determinated with the contact angle measurements. Mechanical properties and mechanism of faliure were investigated with the tensile test on the universal mechanical testing machine. Thermal properties were investigated with differential scanning analysis and thermal stability with termogravimetric analysis. The results of the contact angle measurement with water show poor hydrophilicity of the polylactide surface. Fillers A200 and R816 show hydrophilic and R711 and R816 hydrophobic nature of the filler surface. From the results of the DSC measurements it is visible that addition of the filler has no influence on the PLA glass transition temperature. Addition of the filler increases the degree of crystallinity and shows nucleation effect on the PLA crystallization. In the PLA composites where silica surface is modified with metacryl silane R711 and octylsilane R805 addition of the filler decreases crystallization rate of PLA. Thermal stability is increased with the addition of silica filler in PLA matrix. The results of the mechanical properties showed that addition of silica fillers in the pure PLA matrix did not have any significant effect on the elongation. All curves show maximal elongation at break of 4%, and the best mechanical properties have PLA / R711 composites.

• Keywords: nanokompozitni sustav; biorazgradivi polimeri; polilaktid; silika punilo; međupovršina punilo/matrica; mehanička svojstva; toplinska svojstva
• Keywords (english): nanocomposite; biodegradable polymers; polylactide; silica; filler/matrix interphase; mechanical properties; thermal properties
• Language: croatian
• URN:NBN: urn:nbn:hr:149:386792
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-01-21 13:20:22